Question

In a school, there are 150 students. If 90 of them play chess, 70 of them play both chess and carrom and 40 play none of these games, then find the number of **** who play only carrom.
A. 90
B. 10
C. 20
D. 30

Answer 1

Correct Answer - C

Given n( A) = 90 $(A cup B)=70$
and $n(A cup B)=150 - 40 = 110$
$n( A cup B)=n(A)+n(B)-n( A cap B)$
110=90+n( B)-70
$therefore$ The number of **** who play only carrom = 90 - 70 = 20
Hence , the correct option is ( c)